Definitely this was a very extensive chapter. We recommend to have a second read in the topics you consider more important, also as be said before, remember that if you want a complete understanding of each feature explained, you must research and do proof of concept to get the best option and experience. Due to the nature of our application, the FIFA World Cup is a worldwide event, so you need to make it available for all countries, i18n help us a lot to deal with internationalization with a very easy implementation. If you need to share properties or trigger events between your components, EventAggregator is the best choice. Aurelia offers a very usable variety of binding behaviors, making your code more clean, understandable and maintainable. Value converters, validators, computed properties are just a few binding behaviors that allows developer to reduce code. Remember that many of these features have dependence on third party libraries, so don't forget to download them and configure it into your project bundle. 

We are really sure that this chapter was the most interesting...until this moment! See you in the next chapter!